Written for TV in 1965, Samuel Beckett's 30-minute play – about a man endlessly forced to confront his past – has shades of Krapp's Last Tape, a role already excavated with ravaged power by Michael Gambon. This is the crueller piece. In Atom Egoyan's staging for Dublin's Gate theatre, Gambon plays an elderly man alone in a bare, monastic room, who is clearly afraid of something unseen. His hands tremble as he moves about the cell-like space, enacting a well-worn twilight ritual. He locks the door and checks in the cupboard. He peers under the bed like a nervous child looking for monsters. Only when satisfied that he is safe does he perch on the bed.

But he's not safe. In sealing the room he has created a prison, and locked himself into a past from which there is no escape. And he is not alone. A disembodied voice (Penelope Wilton) attacks him with insidious, predatory intent. It is the voice of a discarded lover taking a quiet, measured revenge for her own betrayal and for all the other women whom Joe once sweet-talked into his bed, lying that "the best's to come" even as he abandoned them.

In fact, he is being attacked on several fronts: by the voice, and by the ravenous eyes of the camera and the audience, too. While Gambon sits almost immobile on the bed, his face is revealed to us in giant video closeup, allowing us to witness the effect of every word on his features. It is like watching a shadow creep across a rugged mountainside. Folds of baggy flesh become a landscape of desolation; eyes that at first seem shifty start to pool with tears, and eventually empty of everything except pain and terror.

There is something enormously uncomfortable here, as if we are in collusion with the voice – indeed enjoying an almost voyeuristic pleasure in seeing a lonely, unloved man get his just desserts. The voice is clever. It is so reasonable, so matey. With its story of "the green one" who did not survive Joe's casual abandonment, it gets us on side. The punishment fits the crime: a man who seduced with words is tormented by them, and reduced to silence. It is an exquisite torture chamber of the mind: remorselessly conceived; remorselessly executed.

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